added translation for the activerecord error messages that occur when the user tries to save a new invalid job offer / chair / student. In the course of this commit the template on how to create yml files for models changed! The README file for locales is updated and also the wiki entry on internationalization. Instead of t("job_offer.title) now one has to call t("activerecord.attributes.job_offer.title"). Through this change it is possible to use already translated yml files from public repositories in order to translate error messages containing the attribute names of models.
added the command rake db:seed to the travis script for deployment
removed the euro symbol out of config/locales/job_offers/de.yml to fix possible deploy error
deleted config/locales/views/job_offers/de.yml to debug the deployment failure
removed inconsistencies between two yml files (de/en)
removed a typo in the de.yml file
added a rake db:drop and rake db:create command for the travis script in order to fix a bug where a loggin in user wants to view a job offer
this is our 'production' system. Would be great if not all data would be removed everytime we add some functionality...
Merge remote-tracking branch 'origin/develop' into develop-js-mail

Conflicts:
	app/views/students/_form.html.erb
	app/views/students/show.html.erb
Merge remote-tracking branch 'origin/master' into develop-js-mail